This project is designed to evaluate the relative effectiveness of two cancer-associated biochemical assays for providing decision-making parameters in the clinical management of patients with breast carcinoma. The two cancer-associated biochemical assays are plasma carcinoembryonic antigen (CEA) and serum fast homoarginine sensitive alkaline phosphatase (FHAP). The two assays will be evaluated individually and as a matrix to determine whether or not they provide clinically useful prognostic information preoperatively, postoperatively, or prior to treatment for metastatic disease. The role of serial determinations of CEA and FHAP levels, individually and as a matrix, for monitoring disease activity will also be investigated postoperatively and in metastatic disease.